Question down there to big for up here....?

Question

A certain uranium isotope loses 1/8 of its mass every century. (Or, phrased another way, the isotope only has 7/8 of its original mass remaining after a century.) We start with 500 grams of this isotope. Find the defining equation of the function which describes the amount of uranium isotope reamining after x centuries.

Answer 1

mass(n) = mass(original) * (7/8)^n

Answer 2

defining equation:

F(c,m)=m-cm/8

m could be any positive number because it is the initial mass of uranium

c (1,2,3,4) ---> it is the century

so in your particular case it would be:

remaining mass= 500 - 500c/8
example
after 2nd century: remaining mass = 500 - 500(2)/8
remaining mass = 500 - 125
remaining mass = 375g


regards, email me if you need more details

Answer 3

m(1) = (7/8)M
m(2) = (7/8)m(1) = (7/8)^2M
so
m = M(7/8)^x, where x is in centuries.
If M 0 500
m = 500(7/8)^x

Answer 4

okay.